What occurrence defines the end of the protostar phase of a star's life and the start of the main-sequence phase?

Carter pushes a bag full of basketball jerseys across the gym floor. The bag weighs 21 newtons. If he pushes the bag 9 meters in 3 seconds, how much power does he use?

What is the momentum of a. 005kg bumble bee that is traveling at a velocity of 3.0m/s?

The planet Mars has much less gravitational force that Earth. What would happen if you went to Mars? A. Your mass would increase. B. Your weight would increase. C. Your mass would decrease. D. Your weight would decrease.

When a virus enters a living cell, the virus a. eats the cell b. makes the cell produce more cells c. dies d. causes the cell to make more viruses

What factor causes the seasons? A: Rotation of earth's axis B: The tilt of earth's axis with respect to the sun C: The appearance of the moon D: An eclipse

Which of the following objects would have the most inertia? A. A sphere with a radius of 5 cm and a mass of 34 grams. B. A sphere with a radius of 4 cm and a mass of 15 grams. C. A sphere with a radius of 8 cm and a mass of 27 grams. D.

A boy slides a book across the floor using a force of five and over a distance of 2M what is the kinetic energy of the book after he slides at assume there is no friction

Where would aliens be if they really do exist here on Earth?

If the mass of an object is 84g and the volume is 12cm3 what is the density

Describe one example of competiton of tropical dry forest